In general, prostheses serve to replace the form and, in particular, the function of limbs which are not present or no longer present. While prostheses made for purely cosmetic reasons do not have to achieve functional objects, prostheses on the lower and upper extremities regularly assume complex problems. Hand prostheses reproduce the function of a natural hand to a large extent, wherein the control of the motor-driven drives in particular requires much outlay.
Prostheses of the lower extremities regularly consist of prosthetic feet, a lower leg tube and optionally a prosthetic knee joint, and are often connected to the remaining stump via sockets. The construction of prostheses of the lower extremities is oriented to the requirements and capabilities of the patients and ranges from a one-axis locking knee joint to computer-controlled prostheses which, on the basis of sensor values, modify the damping properties and engage or switch off drives.
An important aspect in the treatment with prosthetics lies in the correct fitting of the prosthesis to the prosthesis user and the correct assignment of the individual prosthesis components to one another. This alignment of the prosthesis components with respect to one another and to the patient is referred to as the prosthesis alignment or the alignment of the prosthesis in orthopedic technology. Here, the fit and, optionally, the optimization of the settings of upper or below-knee prostheses within the scope of the treatment process is carried out individually for a patient by an orthopedic technician. Here, the orthopedic technician is guided by the alignment instructions and his observations or the impressions of the patient.
In order to assess the alignment, an orthopedic technician can resort to a display system, described in DE 44 01 036 C2, for statistical analysis purposes. The display system provides for a measurement plate and a projection apparatus for visualizing a perpendicular measurement line on the body of a person standing on the measurement plate, wherein the measurement plate is equipped with pressure sensors connected to one another by a circuit, by means of which pressure sensors a drive is controlled, said drive displacing an optical system in a plane parallel to the measurement plate in such a way that a light beam shows the current center of gravity of the person.
US 2008/0285805 A1 has disclosed a system for tracking movements of the human body, in which the movements of the extremities are recorded by 3D inertial angle sensors and wirelessly transferred to an evaluation unit.
WO 2010/120402 A1 relates to a control system for controlling an assigned device with an inertial measurement unit for establishing the orientation of three axes, comprising a computer unit for evaluating the sensor data. The sensor module is connected to the associated apparatus by means of a communication unit and can be controlled thereby. No conclusions about a prosthesis alignment emerge therefrom.